An idiot.
1) Someone who is too stupid to think of a reasoned response to any argument so resorts to attacking someone's grammar and spelling instead.

2) Someone who has failed to grasp that forums are not in fact English essays. Language has always varied according to context, just as we use different types of words in a job interview compared to with our mates.

3) Usually in English forums monolingual native English speakers who utterly FAIL do to the fact that 60% of times they are criticizing someone who is using English as a second language at a far higher standard than the grammar nazi would ever be able to use a second language themselves. 30% of remaining cases the person they are talking to is native English but is dyslexic or 10 years younger. And all 100% of times the person being criticized has much better things to do with their time than correct their every spelling mistake. In either case the grammar nazi fails!

4) Someone unable to figure out the difference between intelligence and correct grammar and spelling.

1) erm.. I don't understand. Brain hurt. Damn why do I have to be so stupid? Oh well- let's just insult his grammar and I'll feel intelligent again.

2)Grammar Nazi"You didn't cite your references or write a proper conclusion- you can get an F for that essay"
Normal Person"erm... Lol it's not an essay its a forum post!!!"
Grammar Nazi"eh? I'm confused? Where am I? Who am I?"

3)Grammar Nazi "You use 'their' not 'there' DUMBASS!"
Janic : Sorry my English isn't up to your standards. My native language is Czech so maybe we should switch to using Czech. As you suggest you are more intelligent than me due to my lack of English logically you must be able to speak fluent Czech as well."
Grammar Nazi "oh... erm... errr" FAIL

4)Grammar Nazi "Your arguments are invalid as you lack the intelligence to use apostrophes correctly"
Philosopher: "Hmmm... Intelligence... what really IS intelligence? In our culture we have learnt to.... (intelligent discussion of intelligence)
(Grammar Nazi's head explodes at this point)

noun (pl. -s)
1. A person who uses proper grammar at all times, esp. online in emails, chatrooms, instant messages and webboard posts; a proponent of grammatical correctness. Often one who spells correctly as well.

2. a – A person who believes proper grammar (and spelling) should be used by everyone whenever possible. b – One who attempts to persuade or force others to use proper grammar and spelling. c – One who uses proper grammar and spelling to subtly mock or deride those who do not; an exhibitor of grammatical superiority. d – One who advocates linguistic clarity; an opponent of 1337-speak. e – One who corrects others' grammar; the spelling police.

proper noun
3. A nickname, pseudonym or handle for a well-known grammar nazi (defs. 1 and 2) within a particular social circle, used to show either great respect or great contempt for his or her abilities.

verb (transitive)
4. To correct the grammar of (a person's speech, a piece of writing, etc.); to edit for grammar and spelling; to proofread.

1. A grammar nazi knows the difference between "there," "their" and "they're."

A captious individual who cannot resist the urge to correct a spelling and/or grammar mistake even in informal settings. After pointing out the linguistic shortcomings in others, a Grammar Nazi feels a strange sense of twisted and unconstructive intelligentsia delight.

In reality, they are making someone else feel bad for no reason and unintentionally implying that their "superior" grammar skills are all they have to show for a wasted liberal arts education.

While proper grammar usage is all well and good, a Grammar Nazi cavils even insignificant errors in English to somehow win an argument. Of course, rather than being genuinely persuasive in an argument, pointing out English errors is a weak attack only on the typist's credibility and never has any bearing on the underlying premises and assertions therein.

In other words, this is simply a disguised ad hominem argument which intelligent and logical people disregard.

Still, one should strive to spell and use words properly, but arrogant and unsolicited advice is not a very persuasive way to teach English.

Average High Schooler: So U R their in Britin, than?

Insecure English PhD (aka Grammar Nazi): I am in England studying here at Oxford, sir, and I prefer you talk to me only in Ye Olde Englishe like a good chap because language can never evolve.

A person who criticizes someone else's grammar, spelling, and/or punctuation, usually in an online setting. While they are often seen as uptight assholes who really need to get a life, it should be noted that they point out simple flaws that often show a lack of intelligence on the part of the person being criticized.

an elitist who gets off on correcting others' grammar and spelling because it makes him feel superior.

grammar nazis often misidentify grammar as the primary determinant of one's intelligence and the most important element of expression.

this belief stems from the grammar nazi's insecurity, which leads him to learn the simplest thing in the whole fucking world to learn and impose it on others, earning self-gratification in the process. realizing how easy but effective it is, the nazi continues this ego masturbation until he can no longer separate the truth from the lie: grammar's not that important, no one gives a shit, and no one likes you.

grammar nazis don't realize that in actuality, grammar is too ambiguous to have a rigid standard, and that though basic grammar is necessary, most grammar rules are not, and can restrict good expression.

Shakespeare: What a piece of work is man! how noble in reason! how infinite in faculty!

grammar nazi: Speak in complete sentences.

Shakespeare: the ability to communicate both colorfully and effectively is way more admirable then perfect grammar so stop sucking Webster's dick, you grammar nazi.